Fluorinated aldehydes and their polymers are known in the art, see for example U.S. Pat. No. 2,568,500, of Husted et al. issued Sept. 18, 1951; U.S. Pat. No. 2,828,287 of Cairns et al. issued Mar. 25, 1958, and a review article on fluoroaldehyde polymers, K. Neeld and O. Vogl., J. Polym. Sci., Macromol. Rev., vol. 16, p. 1-40 (1981). Fluorinated aldehydes form polymers that are useful as chemically and thermally resistant elastomers and thermoplastics, useful for making parts that require these properties, and for films and coatings. Fluorinated aldehydes have been made by a variety of methods.
U.S. Pat. No. 3,067,173 of Barney issued Dec. 4, 1962, discloses various halogenated polyacetals. These polymers contain halogenated .beta.-alkoxy groups. .beta.-alkoxypolyfluoroaldehydes are used in their preparation.
J. D. Citron, J. Org. Chem., vol. 34, p. 1977-1979 (1969), reports that acyl chlorides react with silicon hydrides in the presence of palladium to form aldehydes. No mention is made of the formation of fluorinated aldehydes.
German Patent 3,640,178 A1 published Jun. 6, 1988 describes the synthesis of fluorosubstituted aldehydes by the reaction of fluoroacyl fluorides with silicon hydrides in the presence of palladium or a palladium complex. The use of fluoroacyl chlorides is not mentioned.
J. D. Citron, J. Org. Chem., vol. 36, p. 2547-2548 (1971) reports that acyl fluorides do not react with silicon hydrides in the presence of palladium. However, a reaction to produce an ester does occur when an acyl fluoride and a silicon hydride are heated together.
U.S. Pat. No. 3,208,975 reports that various chelated aluminum compounds, some of which contain alkoxides, catalyze the polymerization of various aldehydes, including trifluoroacetaldehyde. No mention is made of using aluminum compounds containing fluorinated alkoxides.
This invention provides a process for making fluorine substituted aldehydes from available starting materials, particularly making them sufficiently pure so as to be readily polymerizable. This invention also provides novel fluorinated aldehydes and their polymers, a process for making fluorinated aldehyde polymers, and a method for endcapping fluorinated aldehyde polymers.